Smelting-furnace.



PATENTBD JULY 2, 1907. Y

F. T. SNYDBR. SMELTING FURNAGE.

APPLICATION FILED JUNE 19.1908.

2 SHEETS-SHEET 1.

L@ al@ g .PATENTED JULY 2. 1907.

F. T. SNYDER. SMELTING FURNACE.

APPLIOATION ILED JUNI: 18,1906.

2 SHEETS-SHEET 2.

*ata time in a retort.

' or ores of other metals whichare volatile at reducthrough 4the side of the furnace near the smelting 4zone UNITED sTArns PnjrENT OFFICE.-

FREDERICK T. SNYDER, OF OAK PARK, ILLINOIS, ASSIGNOR TO ELECTRIC METALS COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF WEST VIRGINIA.

SME LTING-FURNACE Specification of Letters Patent.

ententes .muy 2, 1907.

Application filed .Tune 18,1906- Berisl No. 322.140.

To all whom 'it may concern:

Be it known that I, FREDERICK T. SNYDER, a citizen of the United States, residing at Oak' Park, in the county of Cook and State of Illinois, have invented a certain new'` and useful Improvement in Smelting- Furnaces, of which the following is a full, clear, and exact description.

My invention relates to a smelting furnace, and is intended more particularly for the 'treatment of ores containing a compound of a metal which is volatile at reduction. For example, my furnace will be especially useful in the treatment of zinc ores, and in cbnnection with such ores an object of this invention is to construct a furnace which will produce spelter as a direct product of the smelting operation, instead of zinc dust.

'The present commercial method of treating zinc oresinvolves the distillation of the ore with carbon lin retorts by means of external heatr This .method is' generally conceded to bea wasteful metallurgical operation, due to the excessive fuel consumption, the destruction of the retorts by corrosive slags, and the loss oflzinc. The method, furthermore, is not a continuous-one, and only a small quantity of ore is treated Attempts have Abeen-made to smelt zinc ores electrica'll'y, in a continuous operation, but heretofore it has been'diicult, if not impossible, to produce any considerable proportinn of the zinc in liquid or compact form aga direct product of the smelting operation, because the zinc vapor produced has been diluted with such quantities of 'CO gas and other impurities that' it would not condense in liquid form, but would be whollyor in large part inthe form of zinc dust, or fio-called blue powder. It has also been proposed to smelt zinc :oresiin a blast furnace'under very high pressure in onderto prevent the zinc fromvaporizing at reduction. 4"This process, however, involves many mechanical d-iculties and the expenditure of'great energy'in forcing the-blast into the furnace against the high internal pressure.

By means of the furnace of this invention, zinc ores,

tion, can be melted electrically under such conditions that the non-condensable gases and the metallic vapor are removed, from the furnace separately, the zinc bei, ing condensed and recovered in coherent liquid form. The furnace is constructed with an outlet for non-con densable vapors through a body of porous material which is being progressively delivered to the furnace chamber, so that metallic products condensed in said porous material will be returned to the heated zone and rie-vaporized. An outlet for zinc is provided but above the slag level, said outlet being' sealed against the exit of gas therethrough, and the Walls arc preferably cooled to condense the zinc, the liquid metal being drained off through said outlet. In treating low grade zinc ores, or ores containing considerable quantities of lead or copper or slag-forming material, the lead may be collected in a body under the bath of molten slag and the copper collected in a matte.

The furnace of this invention will be more particularly explained and further features thereof described by reference to the accompanying drawings, in which,

Figure 1 is a vertical sectional elevation of the furnace on line 1 1 of Fig. 3; Fig. 2 is a sectional elevation-on line 2 2 of Fig. 3; Fig. 3 is aA sectionalpla view online 3 3 of Fig. 1.

The same letters of reference are used to designate the same parts wherever they are shown.

The form of furnace shown. in the drawings consists of a crucible a of lire brick which may be supported in a circular iron casing d1, as shown, and this Crucible is surmounted by a furnace chamber, the lower` side Walls b whereof are made of hollow iron jackets or conduits through which a flow of water is maintained. Above the chamber the side walls of the furnace are continued to form a chute or stack which is open at the top to-receive the furnace charge and to permit the escape ol non-condensable vapors. Through the center of the stack a carbon'electrode c extends downward about the level of the top of the Crucible a to make-.contact with the molten slag in the furnace. The bttom of thecrucible is lled with molten lead, formingth'e other electrode. A lead well d leads outward from the bottom of the Crucible to a point ou t side thefurnace walls, and an electric conductor le dipping into the molten metal 'in the Iead well d serves to'complete the circuit through the furnace from the carbon electrode c. The slag immediately in the vicinity of the electrode c is molten,l but toward the walls of the furnace it is cooler, and o n the walls it is congealed to form alinng therefor, vthis lining being self-renewing, and being kept'from melting by the water jackets. The furnace chamber is preferably rectangular in form, as shown .in Fig. 3, so that the -end walls will be at a greater distance from the.

electrode than the sidewalls. I also preferably maintain a greater volume of water flowing through the end walls; the' result being that there is a greater tendency for the -zinc vapor to condense at the ends of the furnace than near the sides within the zone of gnaximum heat. r

As shown in Fig. 1, the upper rim a" .of the crucible,

which 'may be of fire brick or of congealed slag, is sep arbted a short distance from the water-cooled walls b,,`

I eaying passages g g leading under said walls-and communicating with wells or metal receptacles h h which open outside the furnace. These passages g, which are Ushaped, serve as drains to collect the liquid rzinc which has condensed at or near the watercooled walls b inside the furnace. The liquid metal contained'in the passages serves to connect the slag rim a of the crucible with the water-cooled wall b so as to conduct awayrsuicient heat to prevent'said rim4 from being melted down. The liquid metal held in said U-shaped passages also serves to'prevent ,the exit of gas iromthe furnace through said passages,

and to condense Vzinc vapor coming in contact with said liquid zinc.

The material of the charge is fed iny thiough the open top oi the furnace, a layer of carbon being preferably filled in around. the electrode and the charge heaped up towardl the center', so as vto form an incline down which the larger pieces will tend to roll, theresult beingthat the body of material in the furnace is morev porous toward theoutside, tovfacilitate the passage oi gaseous productsrirom the heated zone toward the wells., Thefurnacev thushas an outlet for non-condensable gases through 'the porous material of. the p chargaquite distinct from .thezoutlet for z inc through which no may pass. The material of the charge surrounds and supports the central vertical electrode;

and forms a porous spacing medium between said lelectrode and the 'waterscooled walls.

There will be .a tendency for4 the in' the passages g to congealupon the water'ackets b, as shown in Fg, 1;'aud IV 4take advantage of this fact'to control the' area of these or outlets `by controlling the supply cix water to the waterfjackets. Valves m 'm are provided vupon the water pipes f or this purpose. By lssening the flow oiwatr through the jacketsthe tendency of the zinc to congeal and close the ps may beovercome, and vice versa, so that the openings maybe `regulated as'desired; or one l. m e may be entirely closed and another'leit open-L- v It 'will be observed'that'a distinctive feature of vapor' in che bodyofnisc'harge. Y 11;v will furthe; be v observed that the gas outlet is arranged to deliver the material therein progressively to the smelting '-f zone of the furnace which is below the zinc outlet,-

so that the )metal condensed in said porous. charge will be etun'ied again to the place' of greater vheat and re-vaporized.- The only escape for thevelatile metal is that provided by the pes g which collect the liquid which been' condensed by the'water .cooled walls. Said walls, which form condeusers for the metallic vapor, may-be constructed of iron.

I will describe the operation of my furnace particup lai-1y in its application to' the treatment of zincflead ore.

l Such ores are preisrablynfirst roasted down to about 8 per centin sulfur; the furnace charge'is made 'up f of itemized om mixed .with carbon-in the form .of coke,

less already in 'the in 'the' desired quan,-

this"- .virnace is the location of an outlet' for zinc above tities) in such proportions as to form what is known as a high temperatureWslag, `that is, a slagwhich requires a high temperature for its formation. Such a slag will be high in lime and silica, the proportion of silica being 50 per cent or more. This slag is desirable in the smelting of zinc ores because it will not retain any appreciable quantity of zinc. The furnace charge will be fed intothe open top ofthe rectangular stack, in the manner previously described, coke being also added around the electrode, as shown.` Current being passed through the furnace between the electrode c andthe conductor e dipping into the lead well; a zone of maximum heat will be established around the lower end of the electrode which will reduce thematerials of the charge, forming gas, slag, matte, lead and metallic zinc, the latter being liberated in the form of vapor. The lead) which is produced sinks to the bottom and adds to the body of molten lead in the Crucible, from which it may be ladled out from time Vto time through the lead Well d. The slag which is formed is molten in the vicinity of the electrode but around the hollow walls through which the water flows, 4it is cong'ealed to form a lining for said walls. The GO gas which is formed as one of the products of the smelting operation escapes through theore body to the top, where it maf;7 be burned. The conditions are such, however, that the escape of the gaseous products is restricted so that a comparatively high pressure is maintained in the cen- -tral portion ofthe ore body. The zincv vapor which is produced, in attempting to escape with the CO gas, becomes condensed in the ore body as the gases leave the central heat zone before -reaching the upper sur-v face. Then as the ore is progressively fed toward the .-heat z one the condensed zinc, which may be in the iorm of dust, -is again brought-intoV the zone of maximum heat-and revaporized, the'result being th'at the miur-A ture pf gas in the furnace is progressively enriched until the percentage of zinc in the mixtureis sufiiciently high soy that thezinc condenses in' liquid form. This liquid zinc collects-in the' coolerrportions of the orel body, which in' the furnace illustrated will beat the end walls,4 and'fmay be drained off under 'said Wallsthrough the passages-g into the wells h, from which it may be ladled;A There lwilll'he no appreciable collection liquid zinc atthe walls nearer the electrode, be-

boiling point oi zinc, extends outward as far as thea-ide Walls, and the zinc within this zoneis vaporized. The

time,y with the slag, and may be settled out o f the'slag andrcovered. l l c While my invention hasbeenparticularly fo'rsmelting lead-zinc oriit will be apparent that it is not limited tosuch` application; and it will also he apparent that,certifilin'features or combinations herein 'dis-,h

dosed win be mangeons in furnaces whichfmay not embody all the other fettine: which are combined in the orm shown itl-the' l The proces herein remises 1111s beenmdsthsgua 12u55 in im application to a hausse, pmiculany'inndeaf jeetof a'separatc applicatiomiial No.. 321,159, ledby manine '11, 190e. csrain'tm femm dimmed.

11o' cause the zoneof-high tempei'ature, which is above the y but not claimed herein are claimed' in my applications, Serial No. 324,116, tiled .lune 20, 1906, Serial No. 324,117, tiled June 30, 1906, and Serial No. 266,541, filed June 23, 1905.

I therefore claim:

1. The combination with a smeiting furnace, of a metrllreceptacle communicating with the interior and exterior of the, furnace but closed against the passage of gas therethrough, said furnace havingl a gas-outlet filled with porous material adapted to condense metallic vapors, said gas-outlet being arranged to deliver said porous material into the furnace. f

2. The combination with a smeltlng furnace, of a metalreccptacle communicating with the interior and exterior of the furnace but closed against the passage of gas therethrough, said furnace having a gas-outlet separate from said metal-receptacle. said gas-outlet being filled with porous material. a conduit filled with iiuid arranged to cool said metal-receptacle, and electric means for heating the furnace to a smelting temperature below the mouth of said metalreceptacle. y

3. ln u smeiting furnace, the combination with a refractory base, of water cooled side-walls snrmounting/said base. said furnace having a slag-tap and an opening through the furnacewalls at a higher level than said slag tap, said higher opening being constructed to hold liquid metal therein to control the escape of gas therethrough, means for maintaining a iiow of .cooling iiuid near said higher opening, and a gas-outlet for said furnace separate from the last-mentioned opening.

4. The combination 4with a smelting furnace, of a metal-` recepi'acle connected by openings with the interior and exterior of said furnace but formed to prevent the passage of gas from said furnacel said furnace having a gas-outlet separate from said metal receptacle, said gas outlet being iilled with porous material adapted to condense metallic vapor means for cooling said metal-receptacle, and electric means for developing the maximum heat'ln said furnace below the opening into said metalsreceptacie.

5. In -an electric furnace, the combination with a refractory base having a crucible therein, of a chamber Wall surmuuntlng said base, said wall being hollow and filled with cooling fluid, the furnace chamber having an open top adapted to receive the materials of a charge and to allow escape ot' the non-( :ondensable gaseous products from said open iop, and a drain between said Crucible and Said wail to collect liquid condensed by said wall, and means for passing an electric current through the material of the charge.

o. ln an electric furnace. the combination with a refraetory base, of chamber walls surmounting said buse, thev lowcr portions oi' snid walls being hollow to receive a cooling iiuid. thc furnace chamber being open at the top to receive the charge4 and constructed to permit the continuous escape ot the uonn1etailic gaseous products, and an opening being provided between the lower part of the chamber wall and the base to allow the liquid metal condcnscd at thc said wall to drain off. l

T, ln au electric zinc-smelling furnace, the combination with a base ot refractory material having a Crucible thorein, oll a watcrjackctcd wall sur'xuountlng said base to forni a I'urnacc chamber, the top ot' said chamber being open. a bath of molten conducting material in said Crucible. a carbon electrode extending down through the open top of the l'urnacc and making electrical connection with said molten bath. said furnace having an outlet. for zinc opening ol't' thc furnace chamber at a point above said molten bath, said outlet being scaled against the passage of gas thcrcthrough. i

B. in an electric Zlnc-snlclting furnace, the combination with base oi refractory material having a crucible therein, ot' a watcracketcd wall surmounting said base to forni a l'urnacc chamber, a 'bath of molten conducting material in said crucihle. n carbon electrodo cxlending down through the open top ol' the furnace and making electrical connection with said nioltcn balli, n rim of solid material al, the cdgc ol' said hath al :l distance from thc wall, said riln cxtcntllng ahovc thc icrcl oi' said hath and l'ornling a dani adaptcd Lo collect thc liquid zinc condensed at said wall,

through said waterjacketed wall, said outlet being s by liquid zinc against the passage of g therethro 9. The combination with a smelting furnace, of u; ceptacle for condensed metalconnecting withthe interior and exterior of said furnace but formed to obstruct the vexit: of gas from said furnace, said furnace having a separate gas-outlet lled with porous material. means for cooling said rceptacle, and electric means for internally heating the furnace charge to a smeltlng'temprature, at a point below the connection of said receptacle with said furnace. v

10. An electric zinc-smeiting furnace, having a gas-ontlet filled with porous material adapted to condense zinc vapor from said furnace, said outletv being arranged to deliver said porous material into the furnace to return the condensed zinc, said furnace having a slag bath therein, means for passing an electric current through seid slag, and a zinc receptacle opening o!! the-furnace above said slag, said receptacle being closed against the, passage of gas therethrough4 containing molten material, of a. metal-receptacle 60mmunlcat'lng with the interior of the furnace above said molten material but closed against the egress of gastherethrough, and a separate gasoutiet for the furnace, independent of said metal-receptacle. I l

12. The combination with an electric furnace, of a condenser formed to prevent vthe passage of gas through said condenser; means for cooling said condenser, said furnace having a gas-outlet independent of said condenser conmaterial.

13. In a smeltlng furnace, the combination with a base, of furnace walls arranged to have an open `top adapted to permit continuous escape of gas, an opening being proopenlng `through the walls located at a higher level than said slag opening, and molten nlctal contained in said higher opening, sealing thc saine against the passage of gas.

14. The combination with au electric smelting furnace, of a water-cooled wall, and a congeaied slag dam inside said wall, liquid metal being collected between said dam and said wall, whereby the heat from said damis conducted to said wall and the melting of said dam prevented.

15. Thc combination with a smeltingr furnace having n plurality of outlets adapted to receive the vaporized or liquid product from said t'nrnace. ot' tillidcarrying.r means for cooling said outlets below tho boiling point of the metal being sxnclied in said l'urnacc, electric means for heating the contenls of'said furnace above the boiling point of said metal. and means t'or scparaicly regulating the iiow oi' cooling iiuid adjacent to the diiiercnt. outlets, whereby the passage through cach outlet may bo restricted by controlling the congcaling oi` lnettal ihcrcin,v

Jil, in a smelting furnace, the combination willi a chaluber-containing an electrode. oi a water-cooled condensing surface forming part. of thc interior sul-taci` ol? the wall of said chamber, and means for collecting liquid metal con dcnsctl by said water-cooled surface said chamber having a continuously open outlet ior gas from thc interior thereof, independent of said condensing surt'acc, incans for condensing and returningI to the furnace contlcnsuble gases passing; to said independent outlet, and a cruriblc base i'or thc furnace, below said condcnsing suri'ncc, adapted to contain inoitcn slag'.

1T. ln an eicctric iurnacc, thc combin.ltion with a cru cibi:` adapted to contain nloitcn rcsisiancc malt-rial. of :l condensing surface extending upwardly ucar tlncdc-c ol' ,i the cruclblc, and n dam or rilu ol' rci'raclori' tnalorial in i icrposcd bciu'ecn`saitl coutlcnsilml sul'l'acenud thc lnoltcn i material adnpicd ro collect und prolccl liuli |ui|l con dcnscd by said surface.

1S. itl a slut-lling t'urnacc. ilul combination with a vortil cai clcclrodc, of wnlcr liaclcctcd sidi-s'4 :lull an outil-b i through aid walcr inclu-t containin'.; liquid zinc .-irranacd l to seal said outlcl :la'aiusl thc pas-sano ol' uns tllcrclhromro i said t'urnacc having a scparallcooled oullol lt-r non con l denslblc gases, indcpcudout ot' said zincoullct.

said furnace having an outletY from said dam letid lnv,c,V

11. The combination with an electric smelting furnace4 vided through the walls to withdraw slag, and a second taining porous material, and means for cooling said porous i 19. In a smelting furnace. the 'combination with a source ot`electric heat. of furnace walls at different distances from said source of heat forming n chamber around the same, u slag-tap through the wall nearer to said source of heat, means for cooling the wall which is farther from the source of heat. to condense metallic vapor, and means for collecting and removing the condensedmetal` 20. The combination with a smelting furnace. of'a re ceptacie for condensed metal connecting with the interior and exterior of said furnace but formed to o'mstruct'they exit of gas from sald"fornace. said furnace having aisepa rate outlet tor gas, independent oi' said receptacle for condensed metal, adapted to permit a continuous escape of non-condensible gases, means for cooling said receptacle, and electric means for heating the furnace chargeA to .a

smelting temperature.

21. The combination with a smelting furnace having a gas outlet nlled with porous material to condense lvapor from said furnace. said outlet being :xrrungedfto deliver said porous material into the furnace to return the condensed vapor thereto, of.' means for cooling saidporous material, said furnace having s slag bath therein, and means for heating said hath with electricity.

22. The combination with an electric smelting tui-nace, of a condenser formed tq' restrict the passage of gas through said condenser, said furnace having a. separate gas outlet` independent of said condenser, said gas outlet containing porous material, and `means for cooling said condenser.

suenos l 23.. The combination with an electric furnace, o! a zinc receptacle having.:l a restricted inlet tcmlnmunica'tlng with said furnace said furnace having a separate gas oli'tlet independent of said zinc receptacle. adapted to permit thc continuous escape of noncondensable gases.

` municating with the interior of the furnace. independently of said gas outlet said condenser being also constructed to restrict the exit of gas therethrough, to maintain said internal pressure. and toforce the non-condensable gas out through said iii-'st mentioned outlet whereby metallic vapor is caused to condense as a liquid.

` In witness whereof, I, hereunto subscribe my name this 16th day ot June, A. 11,1906.

FREDERICK T. SNYDTIR.

Witnesses: v

ALFRED H. Moons, Gnomiz: 1. y-BAn'l'oN. 

